It is absent in the most primitive and symmetrical forms, such as Haliotis and Pleurotomaria.
17, d), we find right and left of the two renal apertures a right and left gillplume or ctenidium, which here as in Haliotis and Pleurotornaria retain their original paired condition.
The heart in Patella consists of a single auricle (not two as in Haliotis and Fissurella) and a ventricle; the former receives the blood from the branchial vein, the latter distributes it through a large aorta which soon leads into irregular blood-lacunae.
9, 10) of _ the nervous systems of ` Patella and of Haliotis, e as determined by Spengel, show the identity in the origin of the nerves passing from the visceral loop to Spengel's olfactory ganglion of the fig..
Limpet, and that of the g ' nerves which pass from the visceral loop of Haliotis to the olfactory patch or osphradium, which lies in immediate relation on the right and on the left side to the right and left gill-plumes (ctenidia) respectively.
- Nervous system of Haliotis; the visceral loop is lightly shaded; the buccal ganglia are omitted.
This sort of Haliotis is also commonly called "ear-shell," and in Guernsey "ormer" (Fr.
The best known and most frequent forms are the asari (Tapes philippinarum), the hamaguri (Meretrix lusoria), the baka (Mactra sulcataria), the aka-gai (Scapharca inflata), the kaki (oyster), the awabi (Haliotis japonica), the sazae (Turbo cornutus), the hora-gai (Trilonium tritonius), &c. Among the cephalopods several are of great value as articles of food, e.g.
" Anomia " (1854), " Mytilus " (1856), " Dentalium " (1856-1857), " Purpura " (1859), " Haliotis (1859), " Vermetus " (1860).
New contrasts are formed by the juxtaposition of differently toned metals; or these with an inlay of haliotis shell, introduced by Alfred Gilbert; or of coloured wax, favoured by Onslow Ford; or enamelling, perfected by Professor von Herkomer; or stained ivory, pearls, or semi-precious stones.